The Influence of Organic Fertilizer on the Seedling Growth of an Oleaginous Species from the Amazon: Andiroba (Carapa Procera Aubl.)

Andiroba (Carapa Procera Aubl) belongs to the Meliaceae family and is a plant of great importance for the traditional medicine in the Amazon. Also, the oil obtained from its seeds is widely used in the cosmetics industry. The following study was carried out at the Tropical Silviculture Experimental Station of the National Institute of Amazon Research (EEST/INPA), where the growth of andiroba seedlings was evaluated using three types of substrates which received daily irrigation, according to the following treatments: T1 = sand/clay; T2 = clay/organic fertilizer and T3 = forest topsoil. The following data were collected monthly: height, neck diameter, and number of leaves. The results showed a non-significant difference with a t-test at a p-value of 0.05 for seedling height. For neck diameter, there was a significant difference, especially in T2 and T3, which presented higher average values, indicating that the use of both commercial organic fertilizer and forest soil which particularly has a high concentration of decomposing organic matter, are beneficial to seedling growth. However, the usage of forest topsoil as a substrate must be taken carefully due to the large amount needed that may harm local ecosystem. Therefore, seedling production with organic substrates is a viable alternative for local producers disposed to produce better quality seedlings.